The field of this invention relates to machine tools and more particularly to an apparatus which is to be mounted in conjunction with a grinding wheel machine tool for the purpose of accurately dressing the grinding wheel.
A machine tool is a power driven machine for shaping metal generally through the use of a series of repeated cutting operations. One form of a machine tool is a grinding machine. A particular type of grinding machine uses a disc-shaped grinding wheel. Every grinding wheel has two components with one being the abrasive, which does the actual cutting, and the bond which is utilized to hold the abrasive together. Typical abrasives would be aluminum oxide, silicon carbide and diamonds. The abrasive is formed into grains with each grinding wheel being constructed of a particular size of grains.
In the shaping of metal, it is common to form lineal grooves within metal plates or annular grooves within cylindrically shaped metallic objects. A common way in which these grooves can be formed is through the utilizing of a grinding wheel. These grinding wheels can be shaped to a precise size and a precise configuration to result in the precise forming of a groove. It is exceedingly common for these grooves to be formed accurately with grinding wheels within a few thousandths of an inch.
The user will purchase the grinding wheel in an oversized condition. The grinding wheel will then have to be "dressed". Dressing a grinding wheel generally includes narrowing of the width of the thickness of the grinding wheel to assume a precise thickness and also possibly accurately forming an inclined bevel within the circumference of the wheel.
In the past, dressing of wheels has been completed directly on the grinding machine. A cutting tool is utilized, usually in the form of a diamond headed cutter which is pressed against the side wall of the grinding wheel, as the wheel is rotated and is moved from the circumference inward a desired amount toward the hub of the grinding wheel. If the resultant groove to be formed is a half of an inch in depth, then it is only necessary to dress the wheel to a depth of a little over half of an inch from the circumference of the wheel.
It is to be kept in mind that accuracy in forming of the wheel is exceedingly important since the wheel is frequently used to reproduce a highly accurate groove within a metallic workpiece. If a single cutter is utilized to dress the wheel, and that cutter is pressed against one side wall of the wheel, inherently the wheel will deflect slightly in a direction away from the cutter. Therefore, as a result, when the cutter is removed from the wheel, the wheel will then deflect back resulting in the side wall of the wheel being ever so slightly inclined relative toits plane of rotation. Now the operator proceeds to dress the opposite side of the wheel and the same problem occurs. Therefore, when the wheel is utilized, the wheel is not formed to the greatest degree of accuracy that may be required in order to reproduce within certain tolerances a groove within the metallic workpiece.